Power consumption is a key constraint in many battery powered communication devices. In some conventional devices, system voltage and clock frequency are set irrespective of actual power requirements which may fluctuate during operation. In fact, in some devices, an actual power requirement may even fluctuate during transmission such that a uniform or slow changing voltage and clock frequency in response to changes in actual system requirements may result in excessive power consumption.
In some communication systems, mobile communication terminals report the amount of data that is pending for transmission. Conventionally, base stations use these reports to allocate sufficient uplink resources to the terminals for transmitting the pending data. For example, the Evolved Universal Terrestrial Radio Access (E-UTRA) specifications, also referred to as Long Term Evolution (LTE), define a Medium Access Control Buffer Status Report (MAC BSR) message, in which a terminal periodically reports to a base station the fill level of its transmit buffer.
MAC BSR is addressed, for example, in “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Medium Access Control (MAC) protocol specification (Release 8),” TS 36.321, version 8.9.0, June, 2010, which is incorporated herein by reference. Sections 5.4.5 and 6.1.3.1 of this specification, for example, define the buffer status reporting mechanism.
Radio Link Control (RLC) data that is available for transmission, for the purposes of MAC BSR, is described in “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Radio Link Control (RLC) protocol specification (Release 8),” TS 36.322, version 8.8.0, June, 2010, which is incorporated herein by reference, for example in section 4.5.
Packet Data Conversion Protocol (PDCP) data that is available for transmission, for the purposes of MAC BSR, is described in “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); Packet Data Convergence Protocol (PDCP) specification (Release 8),” TS 36.323, version 8.6.0, June, 2009, which is incorporated herein by reference, for example in section 4.5.
The description above is presented as a general overview of related art in this field and should not be construed as an admission that any of the information it contains constitutes prior art against the present patent application.